This is a wonderful cape for brds until lvl 54, the lvl where they can get the Jesters Cape (+7 Chr) and the +1 version (+10 Chr).
There is another cape called the Lucent Cape which gives +7 HP +7 MP and +3 Chr and Def 5, that is a better choice than this for Brds and is a lower lvl too but it cost a lot more, around 2-3 mil on the Fairy Server last time I checked.
Besides the Lucent Cape, there is no other cape that I can think of that adds to Songs Accuracy on Mobs, making the Gramary Cape a worthwhile investment.
So if youre very rich, go get the Lucent Cape, if not, then just get this at lvl 50 and the Jester's cape at lvl 54, escpecially since the Gramary Cape is cheap, about 50-70k on the Fairy Server and lower in other servers ive heard.